Apparatus for the practice and study of mathematical tables



R. D. PARKHURST APPARATUS FOR THE PRACTICE AND STUDY OF MATHEMATICALmamas Filed Feb. 10, 1959' 3 Sheets-Sheet 1 INVENIOR ATTORNEYB 7 July19, 1960 R. D. PARKHURST v2,945,303

APPARATUS FOR THE PRACTICE AND STUDY OF MATHEMATICAL TABLES Filed Feb.10, 1959 QS'ShQetB-Sheet 2' L TABLES July 19, 1960 R. n. PAQIRKHURSTAPPARATUS FOR THE PRACTICE AND STUDY OF MATHEMATICA Filed Feb. 10, '19593 Sheets-Sheet 5 INVENTOR fllimmwlzzr MXXXXXXX f 7%fi/ XX 2 W/iATTORNEYS United States Patent APPARATUS FOR THE PRACTICE AND sTUnY Theprimary object of the machine is to provide an fixed to the shaft 28 toprovide apparatus for the study and practice of mathematical tables,such as multiplication tables, to assist in committing the tables tomemory.

Another object of the invention is to provide a device of the classdescribed above having means for blanking out the answers when it is tobe determined how thoroughly the tables have been learned.

A further object of the invention is to provide an apparatus of theclass described above wherein problems of the mathematical tables may bepresented with adjacent means provided to permit the display of possibleanswers to the problem. A,

Other objects and advantages will become apparent in the followingspecification when considered in light of the attached drawings, inwhich:

Figure 1 is a perspective view of the invention;

Figure 2 is a top plan view of the invention taken along the line 22 ofFigure 1, looking in the direction of the arrows with the cover removed;

Figure 3 is a longitudinal sectional view taken along the line 33 ofFigure 1, looking in the direction of the arrows;

Figure 4 is a plan view of the plastic sheet secured to the underside ofthe cover; and

Figure 5 is a fragmentary top plan view of the problem and answerpractice section of the apparatus.

Referring now to the drawings in detail wherein like referencecharacters indicate like parts throughout the several figures, thereference numeral 10 indicates generally an apparatus for the study andpractice of mathematical tables constructed in accordance with theinvention.

The apparatus 10 includes a generally rectangular open topped box,generally indicated at 11, having a bottom wall 12 carrying a pair ofspaced parallel opposite end walls 13, 14 at opposite ends thereof. Apair of oppositely disposed spaced parallel .side Walls 15, 1-6 arepositioned in opposite sides of the bottom wall 12 connecting theopposite ends of the end walls 13, 14. A generally rectangular top wall17 is supported on the upper edges of the end walls 13, .14 and the sidewalls 15, 16 and secured thereto by any suitable means.

A drum 18 is mounted on a shaft 19 having its opposite ends journalledin the side walls 15, 16 parallel to the end wall 13. A spur gear 20 isfixed to the shaft 19 adjacent the side wall 16, as can clearly be seenin Figure 2. A knurled hand wheel 21 is fixed to the shaft 19intermediate the spur gear 20 and the drum 18, for reasons to beassigned. The knurled hand Wheel 21 has a diameter greater than thediameter of the drum 18.

A second dium '22 is fixedly mounted on a shaft 23 parallel to the shaft19 and has a spur gear 24 fixed to the shaft 23 in aligned relation tothe spur gear 20. The shaft 23 is journalled at its opposite ends in theside walls 15, 16. A spur gear 25 is journalled on a stub shaft 26secured to the side wall 16 and is meshed with the spur gears 20, 24, asis shown in Figure 3.

20, 24 are of equal diameter so that the will'rotate equally and in thesame direc- The spur gears drums .18, 22 tion.

A drum 27 is mounted on a shaft 28 journalled in the side walls 15, 16and a knurled hand wheel 29 is also means for turning the drum 27 alongwith its shaft 28.

A shaft 30 has its'opposite ends mounted in the side walls'15, 16parallel to the shaft 28 and has a plurality of wheels 31 individuallyjournalled thereon in axially alignedparallel spaced apart relation.

A shaft 32 has its opposite ends fixed in the side walls 15, 16 and hasa plurality of axially aligned spaced apart parallel rubber hand wheels33 journalled thereon with the peripheral surface of each of the handwheels 33 frictionally contacting the peripheral surface of a respectiveone of the wheels 31.

The cover 17 is provided with an elongated generally rectangular slot 34overlying the central portion of the drum 18 and a second generallyrectangular slot 35 overlying the central portion of the drum 22. Thecover 17 is further provided with a generally rectangular elongated slot36 overlying the center of the drum 27 and a generally rectangularelongated slot 37 overlying the wheels 31. The cover 17 is furtherprovided with an elongated generally rectangular slot 38 arrangedintermediate and parallel to the slots 34, 35 and with another elongatedgenerally rectangular slot 39 arranged intermediate and parallel to theslots 36, 37. j

A relatively short longitudinally extending slot 40 is formed in thecover 17 to permit the knurled hand wheel 21 to extend therethrough.Another relatively short longitudinally extending slot 41 is formed inthe cover to permit the knurled hand wheel 29 to extend therethrough.The cover 17 is provided with a plurality of generally rectangularapertures 42 through which the rubber hand wheels extend.

A generally rectangular transparent plastic sheet 43 is secured to theunderside of the cover 17 by any suitable means to serve as windowclosures for the slots 34, 35, 36, 37, 38, 39 and to carry indiciaunderlying the slots 38, 39. The drum 18 is provided with a plurality ofrows of multipliers, when used for multiplication tables, and theplastic sheet 43 is provided with a plurality of multiplicands indicia44 arranged to underlie the slot 38 and to align with the rows ofmultipliers on the drum 18. The drum 22 is provided with a plurality ofrows of sums arranged to align with the rows of the multipliers and themultiplicands. The drums 18, 22 and the indicia 44 includes all of themultiplication tables from 1X1 equals 1 to 12x12 equals 144.

The cover 17 is provided with a row of mathematical symbols 45indicating the multiplication operation positioned between the slot 34and the slot 38. Another row of mathematical symbols of equal signs 46is positioned between the slot 35 and the slot 38 so that with the drums18 and 22 in a selected position, twelve (12) complete multiplicationproblems are completely illus trated along with their answers. The handwheel 21 provides means for rotating the drums 18, 22 so that each ofthe rows of multipliers, as well as each of the rows of the sums, willbe separately visible through the slots 34, 35, respectively.

The drum 27 is marked identically to the drum 18 and is arranged to berotated by the hand wheel 29 to the desired position. The plastic sheet43 is provided with a second row of indicia 47 which is arranged tounderlie the slot 39 in the cover 17.

The drums 1-8, 22 and 27 are each provided with a blank row showing noindicia so that the device can be set with no problems and no answersvisible during test learned.

The wheels 31 each are identical to one circular row ofthe drum 12-50that'with the-drum 27, indicia 47 and all of the wheels, 31-, all of themultiplication tables from 1 1 equals 1 to 12 12equals 144 may beformed. Army of mathematical symbols 48 indicating the multiplicationoperation are printed on the cover 17 between the slots 36, 39. A secondrow of mathematical symbols 49 indicating the equal signpis-printed onthe cover 17 between the slots 37, 39,. BY Setting the drum 27 to thedesired multiplier, the student can then practice rotating the wheels3-1 through thev rubber band wheels 33 until the answer exposed throughthe slot 37 is his selection for the correct answer to the problempresented by the data exposed through the slots 36, 39. The correctnessof the answer can then be checked by rotating the drums 18, 22 by meansof the hand wheel 21 until the identical problem with 'the correctanswer is exposed on the left side of the apparatus 10.

Obviously, additional mathematical tables, such as subtraction,division, addition as well as simple algebraic problems, may be providedwith the apparatus by changing the indicia on the drums, the plasticsheet and on the.

cover, to provide the desired practice and test material.

Having thus described the preferred embodiment of the invention, itshould be understood that numerous structural modifications andadaptations may be resorted to without departing from the scope oftheappended claims.

What is claimed is:

1. Apparatus for the study and practice of mathemati- 4 V V cal tablescomprising a generally rectangular container, a pair of spaced paralleldrums, each carrying indicia,

journalled in said container, means connecting said drums forsimultaneous equal turning, a cover secured to said container, saidcover having an elongated slot overlying each of said drums, said covercarrying an indicia panel intermediate said slots with said indiciapanel cooperating with said .rowsof indicia, carried by said drums toprovide a plurality of mathematical problems and answers upon rotationof'said drums, a third drum having indicia thereon. journalled in saidcontainer, said cover being provided with a third slot overlying, saidthird drum, a plurality of axially aligned wheels arranged in spacedrelation with respect. to said third drum, and an indicia panelinterposed between said wheels and said third drum to provide, incooperation with said indicia on said third drum, and said wheels aplurality of mathematical problems.

2. A device as claimed in claim 1 wherein means are provided in saidcontainer for individually rotating said wheels.

3. A device as claimed in claim 2. wherein hand operated means areprovided for rotating said drums.

References Cited in the file of this patent UNITED STATES PATENTS511,470 Stone Dec. 26, 1893 1,136,673 Heron Apr. 20, 1915 1,948,712Hornung Feb. 27, 1934 2,643,467 Goodwin June 30, 1953

